Steam-engine.



R. C. STEVENS.

STEAM ENGINE.

APPLICATION FILED MAR. 29, 15H3.

Patented 0013.6, 1914.

QSHEEIS SHEEI 1 f, um;

zgesses 7% f/w UH,

R. C. STEVENS.

STEAM ENGINE.

- APPLIOATION ILED MAR.29, 1913.

' Patented Oct. 6, 1914.

'UNITED STATES PATENT OFFICE.

ROBERT c. sTEvENs, OE'ERIE, PENNSYLVANIA, AsseNoR To sxINNER' ENGINECoM- PANY, OF ERIE, PENNSYLVANIA,

A CORPORATION OF PENNSYLVANIA.

' STEAM-ENGINE. l

T0 all 'whom 'it may concern Be it known that I, ROBERT C. STEVENS, acitizen of the United States, residing at Erie, in the county of Erieandl State of Pennsylvania, have invented certain .new and usefulImprovements in Steam-Engines; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willkenable others skllled in the art to which it appertains tomake and usethe same, reference being had t0 the accompanying drawings, and to theletters of reference marked thereon, formlng part of this specification.y

My invention relates to steam-engines of the type known as centralexhaust engine,

and has for its object the provision of an I exhaust valve in thepist-on body, which is adapted to open` when the central exhaust portshave been uncovered by the piston and to be automatically closed byreason of the compression accumulating behind `the p1ston upon itsreturn stroke, when said piston has traveled a certain po-rtionvof saidreturn stroke. I l

The features of my invention are hereinafter set forth and explained andare illustrated in the accompanying drawings in which:-

Figure 1, is a longitudinal section` on `the line .fr-m in Fig. 2,looking in the directlon of the arrow e, of an engine cylinder andpiston embodying my invention. Fig. 2, 1s a transverse section thereof,on the llne g/-y, in Fig. l looking in the direction of the arrow inFig. l. Fig. 3, is a longitudinal section of the cylinder and a sectionof the piston, on the/line 2 2, in Fig. 2, looking 1n the direction ofthe arrow lw, in Fig. 2. Fig. Il, is a longitudinal section showinganalternative construction of my invention. Fig. 5, is a view in centralhorizontal section of Fig. 2, of the engine cylinder showing the enginepiston in elevation therein looking upward at the inside thereof.

In these drawings, A, indicates an engine cylinder having centralexhaust ports, B.

C, indicates a piston in said cylinder: C, indicates a piston-rod.Within the piston C, I place removable sleeves D, which sleeves aredivided by the transverse wall nl; upon which wall, CZ, there is avalve-stem support d. The sleeves D, have an outturned flange (Z2, onone end thereof, which Specification of Letters Patent.

.closed position until engage an annular shoulder d3, in the body of thepiston (l. The sleeves D, are secured 1n place in the piston C, by meansof screw plugs D', which also close oney end ofv said sleeves D; theother end of the sleeves D, are closed by means of a puppetvalve E,which has a valve-stein E, mounted in and supported by the valve-stemsupport d, hereinbefore described. Secured upon the end of thevalve-stem E', are pistons F, which preferably operate in the sleeves D,between the transverse division wall al, and theA plugs D. Between thedivision walls d, and the valves E, I place Asprings G, which normallymaintain the valves E, in an open position.

Leading inwardly from the end of the piston C, there is a steam passageH, see

Fig. 3), whichterminates in the small pis- 'ton chamber formed bythesleeve D, and

the division wall (l, and the plug D, through which passage compressedair in the cylinder A, and steam may'enter into said small pistonchamber and operate upon the small piston F, therein, to close the valveE, and maintain said valve E, in a l the pressure in the cylinder A, isrelieved by the uncovering of the central exhaust ports B, by the pistonC. In the side of the piston C, I make segmental recesses J one of whichis shown in full lines in Figs. 2 and 3,'. and are indicated by brokenlines in Figs. l, 2 and 3. Referring to Fig. l, it will be seen that thesegmental recesses J, are staggered. From the chamber immediately behindeach of the valves E, an exhaust port K, leads into the segmental recessJ, and from each of said chambers an exhaust duet L, leads into thechamber of lthe opposite small piston F.

It will be noticed that both of the sleeves D, can be removed from thepiston C, by removing the cylinder-head A', without removing the pistonC, from the cylinder A, so that I am thereby able to remove and` replacethe said sleeves D, and the valvemechanism mounted therein, whendesired. In operation, when steam is introduced into the end A2, of thecylinder A, the pressure thereof enters into the passage H, and forceslthe piston F, backward, which action of the piston F, closes the valveE, and compresses the spring G, and at the same time said 'piston coversthe end of the exhaust opening L, thereby forming an air cushionPatented oct. 6,1914, Application filed March 29, 1913. Serial No.757,528.

yeoA

between the pistonF, and the plug D'. Meanwhile the piston C, travelsvbackward toward the end A2, of the cylinder A, and at a point nearwhere the central exhaust ports B, are uncovered by the piston C, the

, pressure in the end A2, of the cylinder 3A,

will be relieved, which also relieves the pressure on the piston F,through the passage H, and permits the spring G, to open the valve B, sothat on the return of the piston C, toward the end A2, of the cylinderA, steam may pass freely through the casing .D, passage K, and segmentalchamber J,

until the end y', of, said chamber, has passed the point, b, of thecentral .exhaust port B, when compression in the 'end A2, of thecylinder A, will begin to accumulate until the intensity thereof issuiiicient to act upon the piston F, through the passage H, to compressthe springA G, and close the valve E, when said valve will be retainedin a closed position until the central exhaust ports B are againuncovered, or nearly so. The action of both the valves shown in thepiston, 'is identical, one valve operating from the end A2, of thecylinder, and the other valve operating from the end A3, of thecylinder.

ln the construction shown in Fig. A, the spring Gr, for opening thevalve E, is dispensed with, and the exhaust passage L, from the chamberof the piston F, is not used, and in lieu thereof the piston F, isprovided with a steam passage, M, leading from the chamber of the pistonF, to the end A2, of the cylinder A.

lllie operation of the construction shown in Fig. A, is as follows, vizz-When the piston C, travels backward toward the end A2, of the cylinderA, the pressure in the end A2, gradually decreases until the centralports B, are uncovered, during which time the pressure in the end A3,communicated through the passage `M, to the chamber of the piston F, hasincreased until the intensity thereof is sutlicient to cause the pistonF, to open the valve B, and hold it open until the piston C, hastraveled backward toward the end A2, of the cylinder A, to reduce thepressure inthe end A2, of the c linderA, and to increase the pressure inthe end A2, of the cylinder A, communicated through the steam passagel-l, in the piston C, to the chamber of the piston F, sucient to causesaid piston F, to close the valve F, and maintain it in a closedpositiony until the piston C, has again uncovered they cen.- tralexhaust ports B, or nearly uncovered them. ln all other respects theoperation of the construction shown in Fig. A, is the same as that shownin Figs. l, 2 and 3.

From the foregoing description and the drawings, it will be obvious tothose skilled in the art, that by the use of my invention,

l can construct a unidow non-condenstirarse ing engine, that is, anengine in which the steam flows continuously from the ends of thecylinder toward the central Vexhaust ports, without the employment ofmechanically actuated' gear for operating exhaust valves. i

Therefore having fully shown and described my invention, so as to'enable others to construct and operate the same, What l claim as new,and desire to secure by Letters-Patent of the United States, is zl.rllhe combination with a steam engine cylinder having central exhaustports, of a piston in said cylinder having exhaust passages thereinadapted to communicate with said central exhaust po-rts, a valve in saidpiston controlling the exhaust to said ports, and'nieans within saidpiston actuated by pressure Within the cylinder for controlling saidvalve during the-compression and admission periods, substantially as`set forth.

2. The combination with a steam engine cylinder having central exhaustports, ofy a piston in sail cylinder having passages adapted tocommunicate with said central exhaust ports, a valve in said pistonadapted to control the exhaust through said passages to said ports,means within said piston to open said valve during the exhaust period ofeach stroke, and means Within the piston actuated by pressure Within thecylinder for closing said valve during the compression and admissionperiod, substantially as set forth.

3. lin a steam engine, a cylinder having central exhaust ports, anengine-piston in said cylindery having steam passage-ways and valve andpiston chambers therein adapted to communicate with said central exhaustduring the -reciprocation of said engine-piston and with the interior ofsaid cylinder, a valve adapted to close said valvei chamber, a'valve-stem thereon, a piston in said piston-chamber secured on saidvalvestein, adapted to be actuated by duid in that end of said cylindertoward which said engine-piston is moving to cause said valve to closethe passage through said valvechamber and retain it in a closed positionuntil the central exhaust ports in said cylinder are uncovered by theengine-piston on its return stroke and means contained within l saidengine piston to operate said valve in the opposite direction,substantially asset forth. y

A. lin a steam-engine, a cylinder having central exhaust ports, anengine-piston vtherein adapted to cover and uncover said ports duringits reciprocation having a valve-chamber and .steam passage-ways thereinadapted to communicate with -said central. exhaust during thereciprocation of said engine-piston, and a piston-chamber and othersteam passage-ways therein in 1,1 lane@ consta-nt communication with theinterior of said cylinder and said piston-chamber and said. centralexhaust, a valve adapted to close communication between the interior ofsaid cylinder and said valve-chamber, a valve-stem thereon, a piston insaid pistonchamber secured on said valve-stem and adapted to be actuatedby fluid in that end of the cylinder toward Which the piston is moving,communicated thereto through some of the steam passages to operate saidvalve to close communication between said end of the cylinder and thevalve-chamber in said engine-piston, and mechanism contained Within saidengine piston adapted to operate said valve in the opposite directionvwhen said central exhaust ports are uncovered on the return stroke ofsaid piston, substantially as set forth.

5. In a steam engine, central exhaust ports, an engine-piston thereinadapted to cover and uncover said central exhaust ports duringitsreciprocations, having therein a valve-chamber in said. engine-piston, adepressed recess in the periphery of said piston, an exhaust portextending between said valve-chamber and said depressed recess, a pistonchamber, a steam passage-Way leading from one end of said engine-pistonto one end of said piston-chamber, and another passage-Way leadacylinder having ing from the opposite end of said pistonchamber to saidcentral exhaust; a valve mounted in said engine-piston, a valve-stemthereon, a piston in said piston-chamber and secured on said valve-stemadapted to be actuated by fluid in said cylinder to cause said valve toclose communication between the interior of said cylinder and thevalvechamber in said engine-piston and retain saidl valve in a closedposition until said central exhaust ports are uncovered by the returnstroke of said engine-piston, and means to move said valve in theopposite direction, substantially as set forth.

6 In a. steam-engine, a cylinderv having central exhaust ports, a pistontherein adapted to cover and uncover said central exhaust .ports duringthe vreciprocations thereof,y having al longitudinal chamber therein, asteam passage-'Way leading from the end of said piston into said chamberand a passage-Way communicating between said chamber and said centralexhaust, a sleeve secured in said chamber having the inner endthereofclosed and a valve-seat opening in the outer end and a valve-stemopening in the closed inner end thereof, a valve seated upon saidvalve-seat opening, a valvestem thereon and extendin into said pistonchamber, a piston in saig piston-chamber vsecured onsaid valve-stem,said engine-piston having a depressed recess in its periphery and anauxiliary exhaust port extendingtherefrom into said sleeve, and springmechanism adapted to open said valve When there is no pressure i thatend of the cylinder, substantially as set forth.

In testimony whereof I aflix myy signature, in presence of tivoWitnesses.

ROBERT C. STEVENS.

Witnesses:

` JOHN B. BRooxs, f I-I. M. STURGEON.

